As one example of plasma processing apparatuses for performing a predetermined plasma process on an object such as a semiconductor wafer or the like, there has been known a slot antenna type plasma processing apparatus for generating plasma by introducing a microwave into a process chamber using a planar antenna having a plurality of slots. As another example, there has been known an inductively coupled plasma (ICP) type plasma processing apparatus for generating plasma by introducing a high frequency power into a process chamber using a coil antenna. These plasma processing apparatuses can generate high density plasma in the process chamber and perform various processes such as oxidation, nitriding, deposition, etching and so on by using the generated plasma.
In view of developing the next generation devices, for example in order to cope with 3D device processing and miniaturization and achieve high productivity, there is a need to increase a diameter of a wafer from 300 mm to 450 mm while securing process uniformity in a plane of the wafer. To this end, there is a need to make uniform a plasma (density) distribution in a process chamber large-sized to correspond to the wafer.
In the slot antenna type plasma processing apparatus, a plasma distribution has been controlled based on shape and arrangement of slots, design in shape of a process chamber or a microwave introduction window, and the like. For example, there was a need of replacement with a planar antenna having other optimally adjusted slot shape or arrangement in order to change the plasma distribution depending on process contents. In addition, also in the ICP type plasma processing apparatus, there was a need of replacement with an antenna having other optimally adjusted coil shape or arrangement in order to change the plasma distribution. However, such antenna replacement was huge effort and time-consuming work for redesign and so on.
A plasma distribution may be adjusted to optimal plasma environments by changing process parameters such as, for example, microwave power, process pressure, flow rate, and so on. However, since these process parameters cannot be separated from process conditions, a range of variation (margin) of the plasma distribution in a changeable range of the process parameters was small and an effect of such adjustment is limited.
In addition, if the plasma distribution becomes eccentric by collapse of symmetry of plasma in the process chamber due to various factors such as manufacturing tolerance, assembly error and difference between devices having the same specifications of a planar antenna, a process chamber and so on, there is no simple means for correcting this eccentricity, which may result in need of big change of devices such as replacement of the planar antenna and so on.
As one example of plasma processing apparatuses capable of improving productivity, there has been proposed a plasma processing apparatus which includes four dielectric line members used to process four targeted substrates having a large area simultaneously, for example as disclosed in Japanese Patent Application Publication No. H8-255785 (JP8-255785A). As another example, there has been proposed a plasma processing apparatus which includes two microwave introducing windows arranged in parallel in order to obtain a uniform plasma distribution for a large-sized object, for example as disclosed in Japanese Patent Application Publication No. H10-92797 (JP10-92797A). In the plasma processing apparatuses disclosed in JP8-255785A and JP10-92797A, microwaves are introduced from a plurality of portions into a process chamber.
Japanese Patent Application Publication No. 2004-128385 (JP2004-128385A) discloses a technique in which microwaves are emitted from four divided antennas and are combined in a space. Japanese Patent Application Publication No. 2009-224493 (JP2009-224493A) discloses a technique for spatially combining a plurality of microwaves introduced from a plurality of antenna modules into a chamber.
In order to make a plasma distribution in a process chamber uniform, as in the plasma processing apparatuses disclosed in JP8-255785A and JP10-92797A, it is considered to introduce microwaves from a plurality of portions into the process chamber and control distributions of a plurality of plasmas produced by these microwaves. However, the technique disclosed in JP8-255785A in which one dielectric line member is provided for one targeted substrate does not consider controlling the distributions of the plasmas. In addition, the technique disclosed in JP10-92797A is hard to control plasma distributions in an extension direction of the microwave introducing windows although it can control the plasma distributions in a direction perpendicular to the extension direction of the microwave introducing windows.
JP2004-128385A and JP2009-224493A do not disclose a detailed method of controlling plasma distributions although they disclose a spatial-combination of microwaves.